2 KIO3 (aq) + 3 N2H4 (aq) → 6 H2O (l) + 3 N2 (g) + 2 KI (aq)
This is an oxidation-reduction (redox) reaction:
2 IV + 12 e- → 2 I-I (reduction)
6 N-II - 12 e- → 6 N0 (oxidation)
KIO3 is an oxidizing agent, N2H4 is a reducing agent.
This is a gas evolution reaction, N2 is the formed gas.